610-27-5

31643-49-9

610-27-5

The general procedure for the synthesis of 4-nitrophthalic acid from 4-nitrophthalonitrile was as follows: 4-nitrophthalonitrile (2 mmol) was dissolved in 5 ml of [bmim]HSO4 ionic liquid and the reaction mixture was heated at 60-65°C for 1-3 hours. The reaction process was monitored by thin layer chromatography (TLC). Upon completion of the reaction, the mixture was poured into water containing crushed ice to induce precipitation of the product. Subsequently, the precipitate is collected by filtration and dried. The product yield of this method was generally higher than 90% and the purity of the product met the requirements without further purification. The filtrate was concentrated under vacuum, washed twice with diethyl ether and concentrated again under high vacuum. After drying, about 95% of the ionic liquid was recovered, and its authenticity was verified by comparison with the original ionic liquid. The recovered ionic liquid showed comparable efficiency to the original ionic liquid in the reaction of converting nitrile to acid and could be reused 5-6 times without significant reduction in activity.